Electrical lamp socket



Aug. 21, 1934. A. SADACCA ELECTRICAL LAMP SOCKET Filed April 28. 1928 I! A LBER75/iD/rCCA lNVEN'ljOR BY A'r ORNEY Patented Aug. 21, 1934 UNITED STATES PATENT OFFICE.

ELECTRICAL LAMP SOCKET Application April 28, 1928, Serial No. 273,451

6 Claims.

This invention relates to electrical lamp sockets.

Where the usual screw socket receptacle is employed for portable electric light circuits such as Christmas tree lighting outfits or other decorative light sets used for outdoor lighting and decoration, it has been found that due to the swaying or vibration caused by wind or other causes, the bulbs not only become disconnected from the circuit, but are loosened to such a degree that they eventually become disengaged from the socket and are broken or injured in ppi It is an object of this invention to provide a lamp socket of the character described in which these difficulties and disadvantages are overcome by a simple and novel construction, which shall be cheap to manufacture and practical and efficient to a high degree.

Another object of the invention is to provide novel screw-shell contact members for electrical lamp sockets having simplified means for fixedly securing said members in their insulating casings against rotary movement on screwing the bulb bases therein.

Other objects of this invention will in part be obvious and in part hereinafter pointed out.

The invention accordingly consists in the features of construction, combinations of elements and arrangement of parts which will be exemplified in the constructions hereinafter described, and of which the scope of application will be indicated in the following claims.

In the accompanying drawing, in which is shown various possible illustrative embodiments of this invention,

Fig. 1 is a front elevational view of a screw socket receptacle embodying the invention fitted with bulb, partly broken away to expose the interior construction;

Fig. 2 is a cross-sectional view taken on line 2-2 in Fig. 1;

Fig. 3 is a front elevational view of the improved screw shell contact member, partly broken away to show the interior construction;

Fig. 4 is a top plan view of the socket shown in Fig. 1 with the bulb removed;

Fig. 5 is a front elevational view of a modified construction partly broken away to expose the interior; and i Fig. 6 is a fragmentary side elevationalview of a portion of the screw shell shown in Fig. 4.

Referring in detail to the drawing, 10 denotes a screw socket receptacle embodying the invention for connection in circuit with the conductor wires 11, and an electric bulb 12.

The socket 10 is seen to comprise a tubular shell contact member 13 preferably made ofspun sheet metal such as brass, and formed with the usual spiral groove or interior thread 14 extending lengthwise thereof. Said member 13 is adapted to receive the threaded or plug end of the bulb base 15 in the well understood manner. As here shown, a suitable casing 16, formed of molded insulated material such as pheno-condensate products or the like substances is provided for snugly fitting about the member 13 and has the conductor wires 11 passing through one end thereof for connecting with said mem- 7 ber 13. The latter has an open or receiving end 13a formed with an outwardly flared flange for limiting the inward movement of the member 13 with respect to said casing. Said flanged end 1341 is provided with one or more inwardly extending rim recesses or slits 130, the purpose of which will hereinafter appear. The inner end 13b of said member opposite said open end is suitably constructed to rigidly carry any insulating closure disc 17 on which is centrally mounted a metallic eyelet 18. The latter serves as the usual central contact of the receptacle 10 and has an end 11a of one of the conductor wires 11 soldered thereto, an end 1112 of the other wire 11 being soldered to an exterior portion of the shell contact member 13 as at 19.

The shell member 13 ordinarily has a relatively loose screw engagement with the threaded bulb base 15, and on screwing the center contact 20 of the bulb base against the contact eyelet 18, said bulb base is tightened in the shell member.

To insure against the possibility of leaving the bulb base loosely connected in the receptacle, or

its becoming accidentally loosened, due to vibration, the shell contact member 13 has a portion of one of its grooves preferably at the mid-height of the shell, pressed inwardly to form a constriction as at 21. Said constriction provides a closely contacting area which functions to take out all loose play of the bulb base 15 in said shell member 13 and frictionally retains the base against accidentally unscrewing or loosening after said base is inserted in its effective mounting position.

In assembling the socket 10, the insulating casing 16 at its open end 16a is heated and the shell contact member 13 inserted. In seating the latter in the casing, the flanged end 13a thereof is pressed into the insulated material about the 110 rim of the open end 16a which is softened and becomes slightly plastic under heat and a portion of said material is forced into'the rim recesses 130 as shown at 16b in Fig. 4. On cooling the casing 16 rigidly secures the member 13 thereto and the insulating material portion 16b positively retains said member against rotary movement with respect to the casing on screwing a bulb base therein.

In Figs. 5 and 6 a modified form of the constricting means is shown. There the shell member 13 has a mid-portion punched and bent to provide an integral spring tongue 121 extending into the path of. travel of the bulb base. The free end of the tongue 121a extends toward the closed end 131) of the member 13 so as not to interfere with the insertion of the lamp base and has an inwardly extending sharp edge portion 121b to form a scraping contact on the lamp base. Thus, in this modified construction, the tongue 121 not only serves as a resilient constriction but obviously also provides an improved contact making means.

It will thus be seen that there is provided a device in which the several objects of this invention are achieved, and which is well adapted to meet the conditions of practical use.

As various possible embodiments might be made of the above invention, and as various changes might be made in the embodiment set forth, it is to be understood that all matter herein set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

1. An electric lamp socket comprising a casing formed of insulating material, a spun metal thimble formed with a screw thread disposed within the casing adapted to receive a standard threaded base of a bulb, said thimble having an outwardly flared rim at its receiving end, said rim having a plurality of spaced cutaway portions. portions of the casing insulating material extending into said cut away portions and portions of said rim being embedded in said insulating material to retain the thimble against rotary movement with respect to said casing.

2. An electrical lamp socket comprising a casing formed of insulating material, a shell contact member formed with a threaded surface extending lengthwise thereof, adapted to engage with a standard screw base of a bulb, said member having an outwardly flared flange at its open end, said flange being formed with a rim having a cut out portion to retain said member against rotary movement with respect to said casing, and portions of said rim being embedded in the insulating material of said casing.

3. The method of making electric lamp sockets consisting in forming a lamp base receiving screw shell having a flaring rim portion with a notch in said rim portion and then pressing said shell into an insulating housing while said housing is heated and in slightly plastic condition for receiving a portion of the softened insulating material thru said notch.

4. An electric lamp socket comprising a casing formed of insulating material, a sheet metal screw shell disposed within the casing, said shell having an outwardly flaring rim formed with a. plurality of notches, the casing insulating material being molded around the notched edge portions of said rim, said rim being thereby embedded in said insulating material to retain the shell against rotary movement with respect to said casing.

5. A lamp socket comprising a casing of insulating material and a threaded shell made of sheet metal within said casing, said shell being provided with an outwardly flaring rim portion engaging said socket, said rim portion being formed with a plurality of spaced notches and intervening projections, said insulating material extending into said notches and said projections being embedded in said insulating material.

6. The method of making an electric lamp socket consisting in inserting into a tubular insulating casing a screw shell having an outwardly flar ing mouth portion formed with a plurality of notches at the rim of said mouth portion and forcing said notched rim into said shell to engage the inner surface of said casing and to partially embed said notched rim in the insulating material of said casing.

ALBERT SADACCA. 

